Harvard researchers create world’s smallest radio reciever from atomic scale defects in a diamond

Image: SEAS

By tech2 News Staff /  19 Dec 2016 , 17:39

Harvard researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have built the world’s smallest radio receiver, made out of atomic scale defects in pink diamonds. The tiny radio is robust and biocompatible, which means it can be used in all sorts of extreme applications, from a space probe headed to Venus to a pacemaker embedded in a human body.

The radio is based on nitrogen vacancy centres, with one carbon atom placed in a tiny diamond with a nitrogen atom and removing the neighbouring atom. The nitrogen vacancy centres are then powered by a green laser. The electrons in the nitrogen vacancy centre are sensitive to electromagnetic waves, including FM signals. When the electrons in a nitrogen vacancy centre receive radio waves, they convert the radio waves and emit streams of red light. This red light stream can be interpreted with a photodiode, that converts the stream of light into a current, which can be converted to sound and heard on conventional speakers.

An electromagnet placed around the diamond can be used to tune in to a particular radio station. Billions of nitrogen vacancy centers can be used to boost the signal, but the radio works even with a single nitrogen vacancy center, emitting one photon at a time. The nitrogen vacancy centers can convert information into light, which potentially allows such tiny structures to be used in photonics, sensors and quantum computers.

Harvard scientists identify aerosol that can cool the planet and repair the ozone layer at the same time

By tech2 News Staff /  13 Dec 2016 , 13:47

The Paris Agreement is a historic global effort to combat global warming by taking steps to reduce carbon based emissions. However, just reducing emissions may not be enough to tackle the problem. A drastic measure for geoengineering the atmosphere is to release large amounts of sulfate aerosols in the atmosphere, which happen naturally after major volcanic eruptions. These aerosols cool down the atmosphere by reflecting sunlight back into space. However, the problem is that the same aerosols also damage the ozone layer, leading to increased risk of UV light exposure.

The UV light exposure can adversely affect human beings, by causing eye damage and increasing the chances of skin cancer. Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have found an aerosol that not only cools the atmosphere, but repairs the ozone layer at the same time. The research is published in the Proceedings of the National Academy of Sciences.

“This research is a turning point and an important step in analyzing and reducing certain risks of solar geoengineering,” said David Keith, the Gordon McKay Professor of Applied Physics at SEAS.  Frank Keutsch, the Stonington Professor of Engineering and Atmospheric Science at SEAS said “Essentially, we ended up with an antacid for the stratosphere.”

Previous research in the area was focused on nonreactive aerosols to reduce the damage done to the ozone layer. The Harvard researchers focused on highly reactive aerosols, that can have potentially beneficial effects. The researchers scanned the periodic table to identify potential candidates for geoengineering. After a process of eliminating unpredictable elements, rare earth metals and toxic substances, Alkali and Alkaline Earth metals emerged as potential candidates.

The researchers are testing the use of calcite in lab environments that simulate the atmosphere. The research teams will be a part of the Harvard Solar Geoengineering Research Program, to be launched next year. The interdisciplinary program is expected to be one of the most extensive and far reaching solar geoengineering research effort ever undertaken.

MIT researchers develop flexible optical fibre for medical implants in the brain

By tech2 News Staff /  18 Oct 2016 , 16:33

A collaboration of researchers between Massachusetts Institute of Technology (MIT) and Harvard Medical School has resulted in the development of highly flexible and stretchable optical fibre for use in biomedical implants within the human body.

The fibre can be used to measure strain, detect signs of disease, or directly treat cells in the human body, especially in the brain. The optical fibre is based on hydrogel, a material made up mostly out of water.

The implants are long lasting and can remain within the human body for extended periods of time. One of the major use case scenario is in a field of medical science known as optogenetics. Here, pulses of light are used to directly activate cells, especially neurons in the human brain. Very thin needle like fibers are used for this purpose. The brain is made up of jelly like material that can be easily damaged by stiff optical fibers. The flexible fiber can allow for therapy over longer durations of time.

Xuanhe Zhao, the Robert N. Noyce Career Development Associate Professor in MIT’s Department of Mechanical Engineering says, “The brain is like a bowl of Jell-O, whereas these fibers are like glass — very rigid, which can possibly damage brain tissues. If these fibers could match the flexibility and softness of